Determination of internuclear angles of DNA using paramagnetic assisted magnetic alignment

Paramagnetic ions have been used to assist the magnetic alignment of DNA. The anisotropy of the binding sites is sufficient to give rise to significant alignment of the DNA with the observed proton-carbon dipolar couplings spanning a 70-Hz range. The dipolar couplings have been used to determine the positions of the axial and rhombic alignment axes. The positions of the alignment axes relative to the positions of the binding sites of the paramagnetic europium ions have also been determined. (C) 1998 Academic Press.